Hitherto, it has been necessary to use an ES cell in order to perform gene modification of a mammal, and hence it has been extremely difficult to create a genetically modified individual except for some animals, such as mice, for which ES cell lines can be utilized. In recent years, however, a new gene modification technology involving utilizing, for example, a zinc finger nuclease (ZFN), TALEN, or CRISPR has emerged to enable genome editing in a mammal to be easily performed through only embryo manipulation without any use of an ES cell (see, for example, Non Patent Literatures 1 to 4).
The technology involving utilizing ZFN or the like is a breakthrough technology which uses a certain sequence on a genome as a target and enables disruption or homologous recombination of a certain gene through an action of a nuclease. In addition, this technology enables gene modification of a target sequence (genome editing) to be easily performed even for any animal for which there is no established ES cell system.
However, utilization of the genome editing technology based on ZFN or the like requires an operation of transferring a nucleic acid into a zygote. The nucleic acid transfer operation is generally performed by a microinjection method (microinjection), which requires a special device (micromanipulator). That is, a problem in cost has been pointed out in the genome editing technology based on ZFN or the like performing by the related-art method.
In addition, a technically skilled person is required for performing the microinjection method, and a problem of low reproducibility depending on experimenters has been pointed out.
As described above, utilization of the genome editing technology based on ZFN or the like for a mammal involves cost and technical problems. Accordingly, there is a demand for a technology which can be readily employed by anyone and can realize genome editing in a mammal with high efficiency.